I wanted carbon for my second bike as well, but my expectations weren't high on the material. I've asked plenty experienced riders before hand about alloy vs carbon, their response "get a new wheel set instead of a new bike". In terms of speed and function, they'd be right if....Practicality was the only reason for my purchase.
I ordered my bmc without even test riding it, I thought it looked that cool and it was on a high discount. As a 61cmer, sizing usually comes down to just getting a 61 without trying other sizes. As for comfort, it takes a lot for me to be uncomfortable on a bike.
Most people just listen to marketing when comparing carbon to alloy. The Alloy Synapse is extremely comfortable. They say alloy is suppose to be rough, but it can roll through countless potholes and absorb most of the vibration. The TMR02 has me feeling rough roads. Weight isn't noticeably different between either bike, although i've never weighed them.